Brad Sigmon, 67, has spent more than two decades on death row. Credit: South Carolina Department of Corrections

Brad Sigmon, a convicted double murderer, has become the first person in 15 years to be executed by firing squad in the United States and only the fourth since 1976.

The 67-year-old spent more than two decades on death row for the brutal killings of David and Gladys Larke. He was executed at Broad River Correctional Institution in Columbia, South Carolina, on Friday, March 7.

Three state corrections department volunteers, hidden from the viewing area, simultaneously fired a round of 100-grain TAP Urban bullets from their .308-caliber Winchester rifles.

Sigmon was strapped to a metal chair, hooded, and dressed in a black jumpsuit with a target placed over his heart. A basin sat beneath him to catch blood.

The execution took place at 6:05PM, and after a doctor examined him for approximately 90 seconds, Sigmon was pronounced dead at 6:08PM, BBC News reported.

Brad Sigmon was seated on the firing squad chair pictured at the back. Credit: South Carolina Department of Corrections

Before his execution, Sigmon used his final statement to urge Christians to oppose capital punishment.

In a message read aloud by his attorney, he cited four biblical passages, arguing that the New Testament does not support execution.

“I want my closing statement to be one of love and a calling to my fellow Christians to help us end the death penalty,” he wrote, per Daily Mail.

“An eye for an eye was used as justification to the jury for seeking the death penalty. At that time, I was too ignorant to know how wrong that was. Why? Because we no longer live under the Old Testament law but now live under the New Testament.”

“Nowhere does God in the New Testament give man the authority to kill another man. That is why the Bible is divided into the Old Testament and the New Testament,” he continued. “Remember the words of Jesus, John 7:19, ‘Did not Moses give you the law? Yet none of you keep with the law.”

He concluded with a statement on divine mercy: “We are now under God’s grace and mercy.”

Sigmon was sentenced to death for the 2002 murders of his ex-girlfriend Rebecca Barbre’s parents, a crime committed just one week after she ended their relationship.

Armed with a baseball bat, he killed David and Gladys by beating them with a baseball bat inside their Greenville County home.

Following his conviction, Sigmon was given two life sentences along with a 30-year prison term for first-degree burglary. His legal team fought for him to serve life in prison instead of facing execution, but a jury ultimately decided on the death penalty.

In South Carolina, condemned prisoners can choose their method of execution. With lethal injection drugs unavailable, Sigmon’s options were limited to the electric chair or the firing squad.

According to Sigmon’s attorney, Gerald ‘Bo’ King, the prisoner avoided the electric chair because it would “burn and cook him alive,” cited by NBC News. “But the alternative is just as monstrous.”

Sigmon also ruled out lethal injection after witnessing the prolonged suffering of three other inmates executed in South Carolina since September.

“If he chose lethal injection, he risked the prolonged death suffered by all three of the men South Carolina has executed since September – three men Brad knew and cared for – who remained alive, strapped to a gurney, for more than twenty minutes,” he explained.

The death row inmate’s execution marks the 1,613th carried out in the US since 1977 and South Carolina’s first by firing squad.